In motor racing, from small amateur go cart races for teenagers up to NASCAR car races for professional race car drivers, the racing vehicles are generally required to use stock tires. It is often against racing rules to treat the stock tires with any chemicals or solvents that will soften the tires so as to improve the ability of the tires to adhere to the track. Allowing such treating of tires may give some racers an unfair advantage and may lead to other problems including pollution. Despite such prohibitions, a small industry has nevertheless developed that sells chemicals that can be absorbed into the rubber material of the tire, and will soften the rubber material of the tire. These chemicals, referred to here as “prep”, generally involve mixtures of hydrocarbon liquids and/or other solvents that soften synthetic rubber. Racing organizations have been trying to develop techniques to catch individuals who are disregarding the racing rules and are cheating by treating their tires with prep.
For example, after particularly important races, tires of the winning vehicles are sometimes removed from the vehicles, and are shipped to a remote laboratory, and are then destructively tested using a gas chromatograph to test for the presence of prep. This type of testing is undesirably expensive and slow. It is desired that the testing be done on the spot at the track and not involve the destruction of the tires.
Accordingly, a handheld device called a durometer is sometimes used. The durometer does not actually detect tire prep, but rather measures the result of using tire prep on a tire, namely the resulting softness of the tire. To use a durometer, a track official typically presses the durometer against the tire such that the durometer compresses a small certain amount of rubber of the tire. The durometer indicates the amount of force required to carry out the compression. Use of durometers to detect tire prep has not been very satisfactory and many cheaters have managed to avoid detection. Some preps do not cause ordinary tire material to soften in a particular way that is detectable by the durometer. A durometer may not detect an unusually soft tire, yet the tire has nevertheless been treated and is significantly more porous and stickier than an untreated tire.
In fact, it has been so difficult to catch cheaters that some racing organizations have been only half heartedly attempting to enforce prohibitions on the use of prep. Many prep mixtures include constituents such as hexane, xylene, toluene, acetone, mineral spirits, paint thinner, transmission fluid, other hydrocarbons, toxic substances, carcinogenic-substances, and flammable substances. At a race track, once a cheater has applied prep to his/her tires, the cheater might be induced to dump the excess prep material on the ground or down a drain in order to avoid being caught with the illicit material. Such dumping causes pollution around the race track and may require the race track to engage in a costly cleanup.
One way of preventing the use of prep is to require racers to purchase a set of racing tires at the track. These tires, once purchased, must be put on the racing vehicle in plain sight, and then the vehicle with the purchased tires is made to enter the race. Due to the open visibility of the tire during this entire process, it is difficult for a cheater to apply prep without being detected. Although this technique can be practiced in auto races of well-known racing organizations where professionals are involved, requiring ah amateur racer with less financial backing to purchase a new set of new tires before each race can be prohibitive. An amateur go cart racer may not be able to afford purchasing a new set of tires every weekend when the racing is only done for recreational purposes. A technique of keeping people from cheating without having to force all racers to buy new tires prior to each race is desired.
Moreover, even at high visibility professional races of national importance, a prepping problem may still occur. Despite the fact that the race teams are required to buy new stock tires at the race track, and despite the fact that race teams are required to put the purchased tires on their race cars in plain sight, each racing pit typically has its own air compressor to inflate tires. Some cheaters have reportedly gone to the trouble of modifying their air compressor so that the outer visible tank includes an inner tank. The inner tank includes prep. As the tire is inflated in the pit using the air compressor, prep from the inner tank is secretly injected into the stock tire. The injected prep then serves to soften the tire from the inside out as the race proceeds, thereby giving the race team an unfair advantage. An inexpensive and reliable technique for detecting tires treated with tire prep is desired.